The Morphology/Morphometry Core laboratory is designed to facilitate performance of morphologic, immunohistochemical, in situ hybridization, and morphometric studies needed for the proposed projects. This Core will provide service, consultation, technical assistance, and or training morphologic and imaging techniques for PPG investigators conducting cell biological and morphologic studies at the histologic and ultrastructural level. This laboratory maintains a full range of light and electron microscopes, ancillary apparatus and preparative resources as well as hardware and software for commuter-assisted image, morphometric, and densitometric analyses. The laboratory is staffed by well-qualified, experienced technicians who will process tissues for light and transmission electron microscopy including immuno- and other histochemical staining and in situ hybridization analyses. The Core director will perform the majority of the morphometric analyses needed by projects II and III. Two key consultants for this Core include Dallas Hyde, Ph.D. who provides expertise in stereology and morphometry of the lung and David Millhorn, Ph.D. who provides expertise in in situ hybridization. All of the major projects and most of the Pilot and Feasibility projects will rely heavily on this unit. This Core's diversity and cost-effectiveness are directly attributable to shared support with other research units using this facility, including a Pediatric Pulmonary SCOR, CF SCOR, and the Center for Environmental Medicine and Lung Biology.